Scientists from the University of Technology Sydney have demonstrated that quantum signals can be transmitted upward from Earth to satellites (Artist’s concept).
Credit: SciTechDaily.com
A new study demonstrates that transmitting quantum signals from Earth to a satellite is achievable, opening the door to more robust quantum communication networks.
Quantum satellites are currently used to transmit entangled light particles from space to multiple ground stations, creating ultra-secure communication links. However, new research has revealed that these quantum signals can also be sent in the opposite direction, from Earth to a satellite, an achievement that was once considered impossible.
This advancement removes several long-standing limitations in quantum satellite communication. Ground-based transmitters have access to greater power, are simpler to maintain, and can produce much stronger signals. These advantages could pave the way for global networks of quantum computers connected through satellite-based systems.
The research was conducted by Professor Simon Devitt, Professor Alexander Solntsev, and a team of scientists from the University of Technology Sydney (UTS). Their findings were recently published in Physical Review Research.
China first entered the field with the 2016 launch of the Micius satellite, which enabled groundbreaking experiments in quantum-encrypted data transmission from space. In 2025, this progress advanced further when the Jinan-1 microsatellite successfully created a 12,900 km quantum communication link between China and South Africa.
“Current quantum satellites create entangled pairs in space and then send each half of the pair down to two places on Earth – called a “downlink,” said Professor Solntsev. “It’s mostly used for cryptography, where only a few photons (particles of light) are needed to generate a secret key.”
Reversing the Flow: The Uplink Challenge
The reverse idea, where entangled photon pairs are created on the ground and sent upward to a satellite, hadn’t been taken seriously. It was thought that an “uplink” approach wouldn’t work due to signal loss, interference, and scattering.
“The idea is to fire two single particles of light from separate ground stations to a satellite orbiting 500 km above Earth, travelling at about 20,000 km per hour, so that they meet so perfectly as to undergo quantum interference. Is this even possible?” said Professor Devitt.
“Surprisingly, our modelling showed that an uplink is feasible. We included real-world effects such as background light from the earth and sunlight reflections from the Moon, atmospheric effects, and the imperfect alignment of optical systems,” he said.
The researchers suggest the uplink concept could be tested in the near future using drones or receivers on balloons, paving the way for future quantum networks across countries and continents using small low-orbit satellites.
Building the Quantum Internet of the Future
“A quantum internet is a very different beast from current nascent cryptographic applications. It’s the same primary mechanism, but you need significantly more photons – more bandwidth – to connect quantum computers,” said Professor Devitt.
“The uplink method could provide that bandwidth. The satellite only needs a compact optical unit to interfere with incoming photons and report the result, rather than quantum hardware to produce the trillions upon trillions of photons per second needed to overcome losses to the ground, allowing for a high-bandwidth quantum link. That keeps costs and size down and makes the approach more practical.”
“In the future, quantum entanglement is going to be a bit like electricity. A commodity that we talk about that powers other things. It’s generated and transmitted in a way that is often invisible to the user; we just plug in our appliances and use it. This will ultimately be the same for large quantum entanglement networks. There will be quantum devices that plug into an entanglement source as well as a power source, utilizing both to do something useful,” he said.
The birth of modern Man
https://chuckincardinal.blogspot.com/
Of course being a philosopher quantum entanglement entices me to consider entanglement of minds, or collective unconscious as some may call it.
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